This invention relates generally to magnetic recording and reproducing apparatus, and more particularly to a magnetic recording and reproducing apparatus of the kind which is automatically adjustable to the proper recording conditions which vary depending on the characteristics of magnetic tapes used for recording.
A conventional magnetic recording and reproducing apparatus of this kind such as a tape deck comprises a plurality of circuit units connected to associated contacts of a change-over switch for the purpose of varying the frequency response of the apparatus and the bias current produced in the apparatus depending on the type or the material of a magnetic tape used for recording. This is because, as is well known to those skilled in the art, magnetic tapes now in use are broadly classified into normal tapes, CrO.sub.2 tapes, Fe-Cr tapes and alloy tapes depending on the kind of the material, and they differ from one another in the recording conditions including the sensitivity, the frequency response and the optimum bias current. Further, even in the magnetic tapes of the same type or the same material, it is not unusual that the aforementioned recording conditions differ from one another depending on the production lot, the maker or the brand. Therefore, in order that the peculiar performance of each individual magnetic tape in use can be fully exhibited, recording must be done at the proper recording conditions for that specific magnetic tape, in addition to the consideration of the kind of the material thereof. Otherwise, the desired flatness of the frequency response during recording and reproduction will not be obtained, and the reproduction of sound with high fidelity will not be achieved.